The present invention relates to highly efficient coding of video data to digital signals with a small amount of codes for efficient data transfer, storage and displaying. Particularly, this invention relates to motion-compensated coding of video data.
Moving picture highly efficient coding in MPEG standards includes motion-compensated prediction. Motion-compensated prediction of interlaced video signals produces relatively many predictive errors due to many spatial aliasing noise components generated in each field of the interlaced videos.
Compared to interlaced video signals, motion-compensated prediction of progressive video signals produces a small amount of predictive errors because of spatial aliasing noise components included in the progressive signals, that are fewer than those in interlaced video signals.
Encoding after interlaced video signals have once been converted into progressive signals thus produces an amount of codes smaller than those produced by encoding of interlaced video signals themselves.
Encoding after video format conversion (interlaced to progressive signals) requires motion vector prediction using video signals to be encoded. Video signals produced by video format conversion exhibits a slight displacement between the original scanning lines and scanning lines produced by interpolation, and contamination of scanning lines produced due to erroneous interpolation, etc. The video signals produced by video format conversion have no problem on subjective picture quality, however, exhibits difficulty in motion vector detection.